As an electrophotographic photosensitive member, which is to be loaded in an electrophotographic apparatus, an organic electrophotographic photosensitive member (hereinafter referred to as an “electrophotographic photosensitive member”) containing an organic photoconductive substance (charge-generating substance) is known. In an electrophotographic process, various members such as a developer, a charging member, a cleaning blade, a paper sheet and a transfer member (hereinafter also referred to as “contact members”) come into contact with the surface of the electrophotographic photosensitive member. Thus, in an electrophotographic photosensitive member, the occurrence of image degradation caused by contact stress with these contact members and the like is required to be reduced. Particularly, with recent improvement in the durability of an electrophotographic photosensitive member, the effect of reducing image degradation caused by contact stress in an electrophotographic photosensitive member has been required to persist.
In connection with persistent contact-stress reduction (mitigation), PTL 1 proposes a method of forming a matrix-domain structure in a surface layer by using a siloxane resin having a siloxane structure integrated in a molecular chain. The method indicates that a polyester resin having a specific siloxane structure integrated therein is used to attain not only persistent contact-stress reduction but also potential stability (suppression of variation) during repeated use of an electrophotographic photosensitive member.
Meantime, there is a proposal in which a siloxane-modified resin having a siloxane structure in a molecular chain is added to the surface layer of an electrophotographic photosensitive member. PTL 2 and PTL 3 propose an electrophotographic photosensitive member containing a polycarbonate resin having a specific siloxane structure integrated therein. These literatures report effects such as improvements in solvent cracking resistance due to mold release characteristics and lubricity of the surface of a photosensitive member at an early stage of use.